Only this much: There are 250 Million blank CDRs and tapes bought and used this year for copying music in comparison to 213 Million prerecorded audio media. This means the owners are only being paid for 46 per cent of the musical content. For a comparison: In 1998 almost 90% of all audio media was paid for.

Of the blank CDRs mentioned in this letter how many were used for non-audio releated activities. You know legit purposes like data back up, sending a copy of my pictures to a friend, theses submission. And so on.
Big time number fudge.